PARIS
— As foreign ministers met in Beirut on Wednesday to discuss the shape of a UN peacekeeping force, France was poised to take its biggest role in decades on the Middle East stage as the force's lead army in Lebanon.

French troops have long been involved in missions in Africa, Afghanistan, and Bosnia, and they participate in the weak UN observer force, now led by a French Army general, which has been based in southern Lebanon since 1978.

But their anticipated deployment, meant to support the cease-fire and enforce an arms embargo in southern Lebanon, marks a shift in France's relations with the Arab world, and with the US, its old rival for influence in the region.

If France has learned any lessons for Lebanon from its experiences as a peacekeeper elsewhere, it is to insist on muscular rules of engagement that allow its soldiers to take the offensive, and fire their weapons, if necessary, says Guillaume Parmentier, a former French Defense Ministry official who is with the French Institute of Foreign Relations in Paris. France will also need a "spoken or unspoken" commitment from Hizbullah to cooperate with UN troops.

"What we want to avoid is what we met when we were in Bosnia before the Dayton agreement, where you have to make peace ... without the proper means," he says. "You can't have a situation where you can only reply when attacked, but can't intervene when things are going on in front of your eyes," he says. "That spells complete disaster, like what happened at Srebrenica."

The UN resolution to end the fighting between Israel and Hizbullah provides for the multinational force to help the Lebanese Army establish control in south Lebanon as Israeli and Hizbullah forces withdraw. It includes an arms embargo, a mission that could mean international peacekeepers are deployed along the Syrian-Lebanese border to stop weapons shipments to Hizbullah from Syria.

While details and rules of engagement are still being worked out at the UN, France has been asked to quickly send 3,500 soldiers to Lebanon, where a jittery cease-fire took effect on Monday. At full strength, the UN force is envisioned at 15,000.

So far, Italy and Turkey have indicated that they are willing to contribute troops. Foreign Minister Philippe Douste-Blazy, in Beirut, did not specify the number of troops France would send, and stated that while France was ready to play an important role in the force, it was vital that many other countries contribute. Germany announced it was willing to contribute to security on the border with Syria.

The Lebanese cabinet, meeting Wednesday, approved the deployment of 15,000 troops to southern Lebanon starting Thursday. Israel had said it will stop withdrawal unless those troops move in quickly. The cabinet appeared divided about Hizbullah's arms, which Hizbullah has said it will not forgo. That has raised concerns about the expectations for peacekeepers.

Douste-Blazy said the arms were an issue for Lebanon's government. He said that the UN force's mandate "is aimed at helping the Lebanese Army deploy, to contribute to the return of the displaced [persons] to their homes, and to the transporting of humanitarian aid."

Reuters reported that plans among Lebanese politicians, military officials, and Hizbullah would call for guerrillas not to carry weapons or use bunkers to fire rockets. There would be no initial demand to move weapons north of the Litani River.

France has rarely been seen by all sides as a neutral broker in the Middle East. Its relations with Israel have long been frosty, and, while it has nurtured ties with Arab countries, it is seen as the patron of Arab Christian minorities, especially in Lebanon.

Analysts say its relations with African nations have been just as complicated. Yet French peacekeeping missions in recent African conflicts are considered successful. "They are quite used to participating in a number of peacekeeping forces, and indeed in more muscular operations such as the Ivory Coast," says Mr. Parmentier.

France has about 10,000 troops stationed around Africa and in French islands in the Indian Ocean. It maintains bases in most of its former colonies.

Since the cold war, however, France has rarely sent its military on missions without cover of international mandate – the UN, NATO, or African organizations. It has often limited its actions to logistical support but has also found itself under attack, as in the Ivory Coast.

Until recently, France's warm ties with Syria might have presented a problem. But President Jacques Chirac, the only Western leader to attend the funeral of former Syrian president Hafez al-Assad, has refused contact since the 2004 assassination of former Lebanese Prime Minister Rafiq Hariri, a friend of Mr. Chirac and leader of an anti-Syrian movement.

French policies in Africa have also moved from blanket support for certain dictatorial regimes in former colonies to more even-handedness. "You see a degree of reluctance on the part of France to intervene in African conflicts, whereas ... in the 1960s, they directly acted in places like Nigeria, Gabon, and Central Africa," says Festus Aboagye, at the Institute for Security Studies in Pretoria, South Africa.

France's biggest and most violent mission is in Ivory Coast, where it operates under a UN mandate to separate rebel and government forces. Two years ago, the Ivorian air force killed eight French soldiers in an attack near rebel positions. France retaliated by destroying the air force. During ensuing riots, French troops fired into crowds, killing as many as 60 people.

"It really damaged their reputation in Africa," says Richard Reeve, an expert at the London think tank Chatham House.

If France is seen in Lebanon as an occupying force, its troops could face similar risks. When France sent a large force to Lebanon in 1983, a suicide bombing of the barracks of a multinational peacekeeping force killed 58 French soldiers, as well as 241 American Marines.